1. Field of the Invention
The present invention generally relates to an attachment for surface-finishing machines, and more particularly relates to a roller wall guard attachment for powered rotary concrete finishing machines.
2. Background Information
Surface-finishing machines are used in a variety of applications to finish a variety of surfaces. These machines include floor sanders, buffers and concrete finishing machines. While the specific configuration of each machine is different, generally these machines are made up of a rotor which supports the structure and assists in moving the device. The rotor may have a variety of attachments including pads, discs, finishing trowels, float pans or other devices attached to it. In the context of a concrete finishing machine, the attachments usually include devices such as rotary trowel attachment blades, float pans or other devices.
The rotor of a concrete finishing machine is usually driven by a motor mounted above the rotor upon a frame. The motor and the machine, in general, are usually controlled by a handle which extends from the frame to a gripping portion where a user can grasp the handle and control the movements of the machine. In most cases, the rotary attachment portion is covered by a protective set of guardrails or a covering. The protective guardrail or covering prevent objects and persons from contacting the circulating parts of the device. These protective coverings are usually circular to protect the entire area where the rotor spins.
This covering portion, while protecting the user from the rotating portion, makes contacting floor surfaces proximate to or adjoining an object having a vertical component, such as a wall, difficult. When finishing machines come into contact with these objects, the protective guardrail or covering prevents the finishing portion of the device from obtaining access to the portions of the surface proximate to the walls or other objects. As a result, the surface portions near these areas are not contacted by the finishing machine and are not appropriately finished. In order for these portions to be finished, they must be finished by another device or done by hand. An example of a typical concrete finishing machine can be seen in U.S. Pat. No. 4,673,311 issued to Marvin Whiteman on Jun. 16, 1987. The teachings of said patent are incorporated herein by reference.
After a concrete surface has begun to set, but before the concrete has hardened (a state referred to as being xe2x80x9cgreenxe2x80x9d), a concrete trowel is used to put a desired finish upon the surface of the concrete. This finish is achieved as the finishing trowels of the concrete finishing machine contact and grind against the concrete surface. The rotating action of the concrete finishing trowels against the concrete surface also acts to propel the finishing machine in a desired direction. This movement can be controlled by the operator lifting up or pushing down upon the handle of the device. By lifting or lowering the handle of the device, the operator can cause the concrete finishing machine to move to the left and to the right while simultaneously moving in a generally forward or backward direction over a concrete surface.
While the concrete finishing machine is moving, the machine may come into contact whit a second surface, such as a wall, post or other object. When the protective cover of the concrete-finishing machine impacts against the wall or object, the finishing machine can damage the wall or object. Sometimes the finishing machine will bounce off of the wall or object and then return to impact the wall again. This process may repeat itself over and over and result in damage to the secondary surface - the surface being finished as well as the surface-finishing machine itself.
Damage can also occur while attempting to hold a surface-finishing machine against a secondary surface such as a wall or object. In this instance, the protective cover vibrating against the wall or object causes damage to the secondary surface. In addition, this impedance of the surface-finishing machine can cause the surface being finished to be scarred and improperly finished.
The impact of the concrete finishing machine against the wall or object can also cause the rotor to rock back and forth and to be moved out of alignment. Both the rocking of the rotor and the spinning motion of the rotor while out of alignment can cause the rotor to become destabilized, and cause wear and damage to the rotor, the motor and other moving parts of the surface finishing machine.
Therefore, what is needed is a surface-finishing device with a wall contact portion that allows the surface-finishing device to finish surfaces proximate to those walls and objets. What is further needed is a surface-finishing device with an attachment that allows the device to finish surfaces proximate to secondary surfaces such as walls and other objects without causing damage to those secondary surfaces. What is further needed is a device that allows a surface-finishing device to finish a surface proximate to a secondary surface such as a wall or object without causing damage to the finishing machine or the surface being finished. What is further needed is a protective device that fulfills these needs that is also retrofittable for attachment to existing surface finishing machines.
Accordingly, it is an object of the present invention to provide a surface-finishing device with a wall contact portion that allows the surface-finishing device to finish surfaces proximate to walls and objects. Another object of the present invention is to provide a device that allows for surface finishing near secondary surfaces such as walls and objects without incurring damage to these secondary surfaces. Another object of the present invention is to provide a device that allows a surface-finishing device to finish a surface proximate to a wall or object without incurring damage to the finishing machine. Another object of the invention is to provide an attachment that accomplishes these objects and is adapted for retrofittable connection with existing surface finishing machines.
Additional objects, advantages, and novel features of the present invention will be set forth in part in the description as follows, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
The present invention is a roller wall guard system for use on a concrete power trowel having a generally circular protective cover made up of a pair of guard assemblies. Each assembly is made up of a generally arc shaped arm having a first end extending to a second end along a desired length. A pivotable connection point, located at an intermediate point along the arm between the first end and the second end, provides a pivotable connection between the guard assembly and the protective cover of the surface-finishing machine. Both the first and second ends of the arm are configured to rotatably hold a roller. Each roller has a diameter and is rotatably connected to the ends of the arm in an orientation so as to allow for rolling engagement of the roller with the secondary surface. The length of the arm and the diameter of the rollers are configured to form a line between a point of rolling engagement of the first roller against the secondary surface and a point of rolling engagement of the second roller against the secondary surface. This line lies outside the circumference of the protective cover.
In use, when contact is made between a first roller and the secondary surface, the arm pivots so that the second roller also contacts the secondary surface. These rollers then direct the surface-finishing machine in a generally smooth line of travel along the secondary surface. Damage to the surface finishing machine, the surface being finished, and the secondary surface is reduced or limited because the rollers of the wall guard prevent the protective cover of the concrete finishing machine from contacting the wall. Furthermore, the force of the contact made by the rollers is directed along the path of travel of the concrete finishing machine.
The wall guards are connected to the protective cover in a way that allows them to be added and removed as desired. This feature also allows the wall guards to be retrofittedly adapted for placement upon existing surface-finishing machines.